A number of years ago, I was dismayed when I learned that Coca-Cola had ceased production of my then-favourite soft drink, Diet Vanilla Coke. I immediately hunted down a couple of supermarkets that had some in stock still, and laid in a supply.
I had no idea that you can't cellar soft drinks the way you cellar wine.
During the past few weeks, in preparation for moving to smaller living quarters, I decided to sample and maybe polish off the supply I had laid in. But I was sadly disappointed.
As I had expected, the two-litre plastic bottle had lost its fizz. What was worse was that even allowing for it's being flat, it tasted horrible. So down the drain it went. A day or two later, I found a twelve-pack of cans that I had also "cellared". With some hope and expectation, I cracked open one of the cans and was delighted to discover the carbonation was still near its peak. One taste, though, and I threw the rest away. It tasted pretty much like the discarded stuff that had been in a plastic bottle (albeit with fizz).
At that point, I wondered if maybe the problem was me, that I had maybe lost my taste for Diet Vanilla Coke; I wondered whether the beverage would cellar just fine in cans but maybe I just didn't like it any more.
Then I came across a twelve-pack of Diet Vanilla Cherry Dr. Pepper that I had laid in about five years ago. I tentatively tried one of those, and it tasted just as bad as the Diet Vanilla Coke had tasted. That led me to conclude that it was the pop, not me.
I guess this means it probably isn't a good idea to try to cellar soft drinks. Too bad.
Digression #1: Apparently Diet Vanilla Coke was revived in 2007. I haven't seen it on the shelves anywhere in our area, though I see that Amazon carries Vanilla Coke Zero. I eagrely await its arrival in our area.
Digression #2: It appears from this site that Diet Vanilla Cherry Dr. Pepper is still in production, but as with Diet Vanilla Coke, I haven't seen it for years. Importantly, this site says that the shelf life of soft drinks containing aspartame is only 3 months. I can understand this now.
Update: A number of years ago, someone who was a knowledgeable (and a bit snooty?) wine afficianado was discussing proper conditions in his wine cellar, etc. etc.. At one point, with a straight face, I asked him the proper way to cellar wine that has a screw cap instead of a cork.